In subsurface fluid distribution systems, such as water pipes in fire suppression systems, it is often necessary to provide valves that are manually operable from above ground and also provide means to easily and visibly indicate above ground the position of the valve. There is a widely utilized valve assembly in use currently that is known as a post indicating valve assembly. Such an assembly includes a butterfly valve comprised of a disk rotatable 90.degree. on a valve shaft within a housing having connector flanges, or the like, to secure to underground pipes, a mechanical actuator to turn the valve shaft and disk between open and closed positions, an above ground indicator, a support column extending between the valve and indicator, a connecting shaft within the column for turning the indicator in unison with the valve shaft, and a torsion spring adjacent the valve shaft to bias the valve disk to the open position against the possibility of a mechanical failure.
In valve assemblies of this type, it is possible to locate the mechanical actuator either below ground closely adjacent the valve, or above ground on the support column, remote from the valve. In the latter form, which is the main subject of this invention, the connecting shaft usually is connected to both indicator and actuator. (Both forms are illustrated in U.S. Pat. No. 3,693,647 to Robert P. Saar.) There are advantages and disadvantages associated with each form.
The mechanical actuator is simply a mechanically advantaged system of worm (or screw) and spur gears to enable an attendant to apply sufficient torque to move the valve between open and closed positions against the force of fluid in the system. Thus, if the actuator is located above ground, where it is exposed to weather and accident but may be easily serviced and replaced if necessary, it may be crank operated and the support column and connecting shaft must be of sufficient strength and rigidity to transmit the torque force to the valve; and since the above ground actuator is easily replaceable, it may be of lighter weight, relatively less expensive construction.
Conversely, if the actuator is in the protected location underground adjacent the valve, the support column and connecting shaft are subject to relatively less torque and thus may be light weight; but the actuator is not available for servicing or replacement without excavating the valve. Moreover, most assemblies of the latter form require a separate drive shaft or wrench by which an attendant turns the buried actuator; and the usual buried actuator form of valve assembly employs a separate access riser between actuator and surface in addition to the column supporting the indicator (which usually is connected by the connecting shaft directly to the valve shaft).
The indicator (known as a "target") must be above ground and, indeed, is usually elevated about 36 inches above grade so as to be visible from a distance of several hundred feet. One indicator embodiment has comprised a stationary cover fastened at the top of the support column, and having plural apertures about its periphery, and a rotatable sleeve within said cover attached to the connecting shaft. The rotatable sleeve has an equal plurality of apertures spaced in its body so as to coincide with the apertures in the cover when the valve is in the open position. Thus it is important that the proper relative positions of the cover, support column and valve housing as well as the relationship between the rotatable sleeve, connecting shaft and valve shaft be maintained when assembling or reassembling the components so that the indicator accurately represents the position of the valve.
The latter relationships have been so important that the post supported valve actuator and indicator are usually fully assembled with the valve at the manufacturing plant and not altered in the field. This practice, while insuring accurate assembly, presents an inventory disadvantage since for any given valve size there are a wide range of column lengths dependent only on the depth to which the valve is to be buried.
Further still, the present post indicator valve assemblies are exposed to above ground accident and impact by reason of the fact that many installations are in fluid lines that are close to vehicular pathways. Moreover, installations remote to such pathways may be at risk from farm and/or maintenance equipment and occasionally off-road vehicles used by inspection personnel. In either instance, there is potential for collision with the above ground portion of the assembly. This can result in damage to both above ground and below ground components. Some control over such damage may be had by breakaway construction of the support column as shown in U.S. Pat. No. 3,452,766 to Fenster. However, that patent does not address concurrent damage to the connecting shaft or the difficulty in replacing the damaged parts in the field. Accordingly, it would also be of great advantage to provide breakaway structure in both the support column and connecting shaft that may be field assembled to be positioned relative to the ground surface level and to be replaceable in the field, when damaged, accurately orienting the parts with respect to the position of the valve.
Accordingly it is an object of the present invention to provide an improved post assembly for a valve having an above ground valve actuator with an easily replaceable breakaway feature for the above ground parts.
Another object of the present invention is to provide an improved post assembly for a valve having an above ground valve actuator with a superior mounting for a spring biasing the valve to an open or closed position.
A further object of the present invention is to provide an improved post assembly for a valve having an above ground valve actuator with means to assure that the parts are properly assembled in accordance with the position of the valve.
The present invention basically involves making both the post outer support column and inner connecting shaft in two demountable parts each being releasably joined at a level slightly above grade (earth surface) in a particular manner that will readily separate and protect the lower (below grade) portions from being damaged should the upper part of the column receive a lateral impact sufficient to cause the column parts to be relatively displaced. In a preferred form the invention also includes orienting means including a multi faceted valve shaft adapter and column flange stud which function to assure that the parts of the post indicating valve assembly are interconnected in proper alignment.